1. Field of the Invention
The present invention relates to a linear guide apparatus which guides a rectilinearly reciprocating object along its moving direction.
2. Description of Related Art
Among linear guide apparatuses used in machine tools, there is a linear guide apparatus which has a rectilinearly formed guide rail and a slider which moves relatively in a longitudinal direction of the guide rail and has a large number of rolling elements incorporated in an interior thereof. In addition, the slider has a slider main body, and the slider main body is configured to include a bearing having a plurality of rolling element raceway surfaces which face rolling element raceway surfaces formed on left and right side surface portions of the guide rail, a pair of end caps which are mounted on one end and the other end of the bearing, a plurality of return guides incorporated in each of the end caps and the large number of rolling elements, and side seats are provided at end portions of the side caps as seal members for sealing gaps defined between the guide rail and the end caps.
In the linear guide apparatus described above, since the rolling elements roll on the rolling element rolling raceway surfaces when the slider moves relatively in the longitudinal direction of the guide rail, there is caused an inherent problem that lubricant needs to be refilled periodically via a grease nipple in order to prevent the seizing of the rolling elements. Thus, in order to solve the problem, there has been proposed a linear guide apparatus in which plate-shaped lubricant application members each having a lubricant application portion which is made of a polymer material containing a lubricant and is brought into contact with the rolling element raceway surfaces of the guide rail are interposed between the side seals and the end caps, respectively (refer to Japanese Patent Unexamined Publication No. JP-A-09-112551).
In the linear guide apparatus described above, the refill of lubricant is made unnecessary to be carried out in the middle of a period of time while it is in service and hence the lubricant can be supplied to the rolling element raceway surfaces and the rolling elements for a long period of time. However, in the event that the amount of lubricant contained in the lubricant application member is decreased to a low level, the lubricant application member in use needs to be replaced with another lubricant application member, although the frequency at which such a replacement occurs is not high. Generally, the side seals and the lubricant application members are fixed to the end caps and the bearing with a plurality of fixing screws. However, when replacing the lubricant application member, the fixing screws need to be removed from the end caps. Due to this, with the linear guide apparatus that has been described above, there has been an inherent problem that many labor hours and much time are required to replace lubricant application members.
In addition, as is disclosed in the JP-A-09-112551, the lubricant application member and the like are fixed in arm portions in a width direction thereof with a plurality of fixing screws from an end face side thereof. Incidentally, there may be a case where the linear guide apparatus described above is used as a guiding member in a slide table apparatus. In particular, as the configuration of such a slide table apparatus, a configuration is used in many cases in which two guide rails are used, two or more sliders are combined with each guide rail, the two guide rails are fixed to a base in parallel to each other, and the respective sliders are fixed to a lower surface of a slide table. In this case, as is shown in FIG. 58, in the event that a slide table b of a slider table system is fixed to an upper surface portion of a slider main body a, when attempting to replace a lubricant application member c whose lubricant content is low with a new lubricant application member, it becomes extremely difficult or impossible to remove and refasten fixing screws disposed, in particular, in a portion hidden by a lower side of the slide table b (in particular, in the case of the slider shown in FIG. 58, a portion of a left-hand side lubricant application member c where a far-side arm portion thereof lies). Therefore, since the lubricant application member c cannot be removed from a guide rail d in such a state, the lubricant application member c needs to be replaced after the slide table b has been removed from the slider main body a. Because of this, many works and much time have been required to remove the slide table b.
In addition, it is considered to reduce the frequency at which lubricant application members are replaced or to obviate the necessity of replacement thereof by separately providing a tank or the like and a fluid supply apparatus which are necessary to refill lubricant to the lubricant application members. However, when attempting to mount the tank or the like externally, an extra space will become necessary for the tank or the like. Further, when attempting to provide the tank or the like within the slider main body in order to save space, deterioration in strength of the slider and a complex construction will be called for. In addition, the provision of the fluid supply apparatus will also result in calling for complex equipment including piping and the like.